1. Field of the Invention
The present invention relates to an arrangement structure for a sensor to be mounted to an engine of a vehicle, wherein the engine is arranged in an engine compartment of the vehicle in a posture allowing a crankshaft of the engine to be oriented in a widthwise direction of the vehicle, and the sensor is mounted to a lateral surface of the engine.
2. Description of the Background Art
Heretofore, there has been known an internal combustion engine for a vehicle, which comprises a crankshaft rotatably supported by an engine bock, a compressor mounted to the engine block through a bracket, and a crank angle sensor mounted to a vehicle-frontward wall surface of the engine block facing in a frontward direction of the vehicle, while being exposed outside the engine block, wherein the bracket is provided between the engine block and the compressor, and the crank angle sensor is disposed at a given position of the vehicle-frontward wall surface of the engine block covered by the bracket, as disclosed, for example, in JP 2005-30311A.
In the structure disclosed in the above Patent Document, the crank angle sensor mounted to the vehicle-frontward wall surface of the engine block is covered by the compressor-mounting bracket. This provides an advantage of being able to protect the crank angle sensor against a pebble and water coming in from a front end of the vehicle during traveling of the vehicle.
However, in case where a crank angle sensor is mounted to a vehicle-frontward wall surface of an engine facing in a frontward direction of a vehicle as in the structure disclosed in the above Parent Document, for example, in the event that a relatively large amount of water comes in from the front end of the vehicle, the incoming water is likely to reach the sensor through a small gap or the like and wet the sensor, even if the sensor is shielded by a member, such as a bracket, which is liable to cause adverse effects on performance of the sensor.
Therefore, in view of more reliably prevent the sensor from being wetted by water coming in from the front end of the vehicle, it can be said that it is desirable to mount the sensor to a vehicle-rearward wall surface of the engine facing in a rearward direction of the vehicle, instead of the vehicle-frontward wall surface of the engine. However, even if a mounting position of the sensor is simply changed to the vehicle-rearward wall surface of the engine, it is unable to eliminate a possibility that a foreign object, such as a pebble kicked up by a front wheel, hits the sensor, and there remains a risk of being unable to maintain performance of the sensor on a long-term basis.